(As in Ship's Log)
Special bonus-word: Knot
Definition: In the early Age of Sail (very setting-relevant), navigation was still in its infancy. The most high-tech instrument on a ship was the compass, but that only gave the navigator the bearing. To find the longitude, the sailors would use a knotted rope attached to log -- at set intervals, the log would be lowered into the water, and the mariner would count the knots as the log drifted away from the ship (we still measure nautical speed in knots). This would be recorded meticulously in a journal (the ship's log). Using these data the navigator would find the longitude of his intended destination, then set a course by the compass.
Source: The Savage World of Solomon Kane, Pinnacle Entertainment Group; and Classic Encyclopedia